NT Part F7 Sound transmission and insulation
Introduction to this Part
This Part is intended to reduce the likelihood of illness or loss of amenity as result of undue noise transmission between different parts of a building or adjoining buildings. This part contains minimum requirements for sound insulation for walls, floors and penetrations through walls and floors for services such as pipework.
NT F7P1 Sound transmission through floors2019: NT FP5.1
Floors separating sole-occupancy units must provide insulation against the transmission of airborne and impact generated sound sufficient to prevent illness or loss of amenity to the occupants.
NT F7P1 only applies to a Class 2 or 3 building or a Class 9c building.
NT F7P2 Sound transmission through walls2019: NT FP5.2
- sole-occupancy units; or
- a sole-occupancy unit from a plant room, lift shaft, stairway, public corridor, public lobby or the like,
must provide sufficient insulation against the transmission or airborne or impact generated sound sufficient to prevent illness or loss of amenity to the occupants.
NT F7P2 only applies to a Class 2 or 3 building.
NT F7P3 Sound transmission through wall and floor penetrations2019: NT FP5.3
The required sound insulation of floors and walls must not be compromised by the incorporation or penetration of a pipe or other service element.
NT F7P3 only applies to a Class 2 or 3 building or a Class 9c building.
NT F7P4 Sound transmission through walls in residential care buildings2019: NT FP5.4
- sole-occupancy units; or
- a sole-occupancy unit from a kitchen, bathroom, sanitary compartment (not being an associated ensuite), laundry, plant room or utilities room,
must provide insulation against the transmission of airborne sound sufficient to prevent illness or loss of amenity to the occupants.
NT F7P4 only applies to a Class 9c building.
NT F7D1 Deemed-to-Satisfy Provisions2019: NT F5.0
NT F7D4 Sound insulation of floors between units2019: NT F5.3
A floor separating sole-occupancy units must have an RW not less than 45.
NT F7D5 Sound insulation of walls between units2019: NT F5.4
A wall must have an RW not less than 45 if it separates—
- sole-occupancy units; or
- a sole-occupancy unit not within a Class 9c building from a plant room, lift shaft, stairway, public corridor, hallway or the like; or
- a sole-occupancy unit in a Class 9c building from a kitchen, bathroom, sanitary compartment (not being an associated ensuite), laundry, plant room or utilities room.
NT F7D6 Walls between a bathroom, sanitary compartment, laundry or kitchen and a habitable room in adjoining unit2019: NT F5.5 and NT Table F5.5
- have an RW of not less than 50; and
- provide satisfactory insulation against impact sound; and
- not incorporate a duct which reduces the RW of the wall to less than 50.
- in accordance with (3); or
- for other than masonry, in 2 or more separate leaves without rigid mechanical connection except at their periphery; or
- identical to a prototype that is no less resistant to the transmission of impact sound when tested in accordance with NT Specification 29 than a wall listed in (3).
- Cavity brickwork: two leaves of 90 mm brick masonry with—
- all joints filled solid with mortar; and
- an air space not less than 40 mm between the leaves; and
- the leaves connected only by ties in accordance with AS 3700.
- Single leaf brickwork: 110 mm thick brick masonry with—
- each face rendered 13 mm thick; and
- 50 mm x 12 mm thick timber battens at not more than 610 mm centres fixed to each face but not recessed into the render; and
- one layer of 12 mm thick softboard nailed to the battens; and
- 6 mm thick medium density hardboard adhesive-fixed to the softboard.
- Concrete blockwork: 190 mm thick concrete block masonry with—
- each face of the blocks fitted with 50 mm x 50 mm timber battens, spaced at not more than 610 mm centres, screw-fixed into resilient plugs with rubber inserts; and
- the space between the battens completely filled with mineral or glass wool blanket or batts not less than 50 mm thick; and
- the outer face of the battens finished with plasterboard not less than 10 mm thick or other material with a mass per unit area not less than 7.3 kg/m2.
NT F7D7 Soil and waste pipes to be separated2019: NT F5.6
If a soil or waste pipe, including a pipe that is embedded in or passes through a floor, serves or passes through more than one sole-occupancy unit—
- the pipe must be separated from the rooms of any sole-occupancy unit by construction with an RW not less than—
- 45 if the adjacent room is a habitable room (other than a kitchen); or
- 30 if the adjacent room is a kitchen or any other room; and
- a door or panel provided access to the pipe must not open into any habitable room (other than a kitchen); and
- an access door or panel in any other part must be firmly fixed so as to overlap the frame or rebate of the frame by not less than 10 mm, be fitted with a sealing gasket along all edges and be constructed of—
- wood, particleboard or blockboard not less than 38 mm thick; or
- compressed fibre reinforced cement sheeting not less than 9 mm thick; or
- other suitable material with a mass per unit area not less than 24.4 kg/m2.
NT F7D8 Isolation of pumps2019: NT F5.7
A flexible coupling must be used at the point of connection between the service pipes in a building and any circulating or other pump.